Multiple Solrs on the same box

[Simon Wistow <si...@thegestalt.org>]

First, a couple of assumptions.

We have boxes with a large amount (~70Gb) of memory which we're running 
Solr under. We've currently set -Xmx to 25Gb with the GC settings

-XX:+UseConcMarkSweepGC 
-XX:+UseParNewGC 
-XX:+CMSIncrementalMode 
-XX:+CMSIncrementalPacing

We're reluctant to up the -Xmx because when stop the world GC does 
eventually happen it'll be pretty devastating. But we also have a bunch 
of spare memory lying around.

So we're wondering if running multiple Solrs is the right thing to do - 
that way we'll be using all our memory without very long GC pauses. 

Of course, if that assumption is wrong then the rest of this mail is 
irrelevant. 

We're currently using Tomcat but we're pondering moving to Jetty but 
whilst I've managed to get multiple Solr apps running on different ports 
under the same Jetty instance I can't seem to get them configured via 
JNDI.

It looks like someone put a tar ball with details of how to do that on 
the Wiki 

http://wiki.apache.org/solr/SolrJetty#JNDI_Caveats_Noted_By_Users

but the permissions have been set so that you can't actually download 
it.

So - three questions really:

Am I barking up the wrong tree or is multiple instances a good idea?

Is Jetty worth it or should I just stick to Tomcat?

Can someone set the permissions on the wiki so I can download that file?
;)


cheers,

Simon